Dr. Konstantinia Papadimitriou is a chemist with a Master’s and PhD from the University of Patras in Greece. During her PhD, she studied polymers for energy applications, particularly synthesis and characterization of polymers for fuel cells.
Following her doctoral studies, she conducted postdoctoral research at the Foundation for Research and Technology Hellas / Institute of Chemical Engineering Sciences (FORTH/ICE-HT), focusing initially on polymeric membranes for fuel cell applications, and then on graphene-based nanocomposite materials.

For the past seven years, she has held the role of project manager at Admiris. Her responsibilities include the sourcing of raw materials. She specializes in identifying and matching both primary and secondary materials with customer needs, particularly in metallurgical applications.

How can you describe your role within the Hephaestus project?
In the Hephaestus project, my main focus is on the sourcing of industrial residues such as AOD (Argon Oxygen Decarburization) and EAF (Electric Arc Furnace) dusts from the steelmaking process. To do that effectively, I need to understand exactly where in the process these by-products are formed, and I search for data like their chemical composition and mineralogy, the production rates, and how these sources are currently being disposed of or valorized. I also identify the major producers. 

I am leading Work Package 2, which is the EU sites and waste assessment, which is focused on sourcing and evaluation of input materials for HEPHAESTUS processes, along with the identification of the optimum raw materials supply chain and the most promising geographical regions for technology implementation. This work package consists of three tasks. The first two are already completed. In the first task, the focus was on the sourcing of EAF and AOD dusts from the steelmaking industry. In the second task, I sourced other types of industrial materials, not limited to dusts, to be tested by our partners at NTUA and CSM. These came from different industrial sectors, including mining and metallurgy.

These waste materials have several potential uses. Some are being evaluated as fluxes or as additives to modify the composition of slag for the subsequent mineral wool production. Others may serve as raw materials for the recovery of valuable elements like Zn, iron, etc.. The challenge lies in identifying the right material for the right application and matching it with the technical needs of our project partners. Based on this, in Task 3 we will choose the optimal raw materials supply chain and find which regions are most suitable for building the Hephaestus plant.

Dust is not the main waste stream in steelmaking. Why focus on it?
You are absolutely right. In terms of volume, iron and steel slags are by far the largest waste streams in steel production. In 2024, global production of blast furnace slag was estimated between 330 and 390 million tons, while steel slag accounted for roughly 190 to 290 million tons. In Europe alone, data from the EUROSLAG association shows that in 2023, around 14.7 million tons of blast furnace slag and 8.5 million tons of steel slag were produced.

Slag, especially Ground Granulated Blast Furnace Slag (GGBFS), already has well-established uses in construction. It is commonly used as a cement additive and competes with other materials like fly ash and volcanic pozzolans.

Though smaller in volume, steelmaking dust waste stream should not be underestimated. The EU still generates about 1.2 million tons of EAF dust each year, and that is not a small amount! This EAF dust is classified as hazardous waste in many regions. Landfilling is not only expensive due to strict regulations, but also risky, as it can lead to the leaching of heavy metals like lead, cadmium, and zinc into the environment.

What makes EAF dust important is its high content of valuable metals, especially zinc and iron. In fact, EAF dust can contain anywhere between 15 and 35 percent zinc, and sometimes even up to 40 percent. This much higher than the levels typically found in dust from stainless steel production. And zinc is a strategic material which is widely used in galvanizing steel, as well as in batteries, alloys, and coatings.

Currently in Europe, about 80 percent of high-zinc EAF dust is treated using the Waelz process for zinc recovery. But there is a catch: around 80 percent of the treated residue from this process still ends up in landfills. Although the HEPHAESTUS project is still ongoing, early results show that the our process is capable of recovering zinc even from dust with lower zinc content, under 15 percent. This shows one of the main benefits of the HEPHAESTUS technology: it creates almost no waste, unlike the Waelz process which still leaves a lot to be landfilled.That is a big step forward! 
To conclude: from a business point of view, we do not want to lose all that zinc. And from an environmental point of view, the risks and costs of hazardous waste disposal are simply too high to ignore. That is why we believe EAF dust deserves our full attention.

What are the main (non-confidential) outcomes so far?
Task 1:
We calculated that the crude steel production in the EU amounts to 129 million tons, with 45 percent of this coming from electric arc furnaces. In the EU, we have 148 EAF furnaces with a total production capacity of 90 million tons per year. Additionally, there are 45 plants that produce stainless steel and specialty steels, and these plants except the EAF dust they also produce AOD dust. From all this production, between 57,130 – 262,798 tons of EAF and AOD dust are generated annually. The main steel-producing countries in the EU are Germany, Spain, Italy, and France.
We can conclude that there is enough dust available for valorization, and a large portion of it contains valuable metals like zinc, iron, and lead, which are typically landfilled and wasted. Hephaestus is capable of handling dust with low zinc content, which is not feasible with conventional Waelz process.

Task 2:
We have identified 46 wastes and byproducts, beyond just EAF/AOD dust, that could potentially be processed using Hephaestus technology. We identified 5 categories of wastes/by-products being: 
1.    Wastes/by-products from ironmaking and steelmaking.
2.    Dusty wastes produced from EAFs from ferroalloys production e.g. FeCr alloys. 
3.    Fine tailings and wastes from the extractive industry e.g. marble powder wastes.
4.    Metallurgical slags.
5.    Wastes or by-products from other industrial activities within Europe e.g. lime sludge produced in the paper industry.
For all these materials, we have detailed sourcing information. We share this data with the technology providers of the project to decide which materials they want to test in lab-scale trials. The technology providers selected 13 wastes and received samples from the producers for testing.

Why focus on these “alternative wastes”? The goal is to substitute primary raw materials with secondary ones in the HEPHAESTUS technologies: either as fluxes or to adjust the chemical composition of slags in the CleanTech furnace for mineral wool production, or as feedstock for CRM extraction. The end goal is to create an integrated waste valorization strategy.

Task 3:
This task is about the implementation of HEPHAESTUS technologies and is the most exciting one. It focuses on finding the optimal supply chain and identifying the best regions for implementing waste valorization with Hephaestus technology. We are looking at regions with large EAF plants, such as northern Italy, northeastern Spain, and the border areas between Germany and France, including Luxembourg.
The next step is to create an integrated map with raw materials producers and the customers of HEPHAESTUS products and calculate logistics to determine the best location for the Hephaestus plant.

What are you most proud of in your work with Hephaestus?
There are many aspects of my work that I am proud of. Focusing on sourcing has given me insight into a wide range of waste types across different industries, significantly broadening my perspective. I have learned a great deal, and this knowledge has been crucial to the project, especially in assessing the quantity and quality of waste, identifying the producers and production sites, and understanding the market potential for HEPHAESTUS products. Ultimately, all of this contributes to laying the foundation for building the plant. It is also rewarding to know that my efforts support a greener, more sustainable future for the steel industry. 

What makes Hephaestus relevant in today’s industrial landscape? 
In short, Hephaestus directly addresses the urgent need for a cleaner industry, smarter waste management, and sustainability. By recycling metals and turning slag into valuable materials, this project demonstrates to the steel industry how they can close resource loops and reduce their reliance on raw materials. In doing so, it supports the principles of a circular economy.

Furthermore, it aligns with the goals of the Green Deal to reduce greenhouse gas emissions. Looking ahead, if everything goes as planned, we could also contribute to boosting local economies. This could lead to lower transportation costs, more customized waste valorization, and the creation of local jobs.

How do you want to see the future of the steel industry?
In the next few years, I do not expect drastic changes. However, my vision, or my dream, is to see a more sustainable steel industry. One where hydrogen and renewable energy is used instead of coal. I also envision a future where we recycle more scrap metal, which is achievable in the near term. This would reduce energy consumption and the need for raw materials.

We need to better manage and reduce industrial waste and find ways to reuse it, because so much of this waste can actually be valorized. Another key point is designing steel products with reuse in mind. From the very start of the production process, we should think about how the products will be recycled to minimize waste. A circular economy approach must be adopted, particularly in high-capacity plants. For example, large-scale plants should install carbon storage and capture systems. Within Hephaestus, we aim to convert captured CO₂ into methanol.

It is also essential to have transparency regarding real emissions and progress toward reducing steel waste and emissions. Public disclosure of this information is key.

Government support will also be crucial. Environmental policies should encourage cleaner practices, offering incentives to industries transitioning to green energy and sustainable products.

To know more about Admiris, visit their website.